The nutrient requirements for animals, particularly those animals of the type raised for food, such as beef cattle, have been studied in substantial detail so as to determine how much food and what types of foods should be supplied to the animals in order to achieve a desired rate of growth. One such study is reported in a publication by The National Academy of Sciences, entitled "Nutrient Requirements of Beef Cattle" (5th Revised Edition, 1976, No. 4), wherein the body weight of beef cattle is compared with a daily average gain in weight, daily dry matter ingested by the animals, and a listing of required protein, calcium, phosphorous, carotene, and vitamin A for the growth rate. The cattle classes listed included "Finishing Steer Calves", "Finishing Yearling Steers", "Finishing Two-Year Old Steers", "Finishing Heifer Calves" and others. Other sources provided nutrient values for various foods, such as Fescue hay, corn grain, soybean meal, etc. With a use of information of this type, precise amounts of food substances can be provided to cattle for an expected daily growth rate.
Various diet buffers and additives also have been developed for beef cattle and other animals which cause the animals to have a growth rate faster than they ordinarily would have on a given diet. For example, limestone has been added to the cattle feed which would comprise, for example, various hay and grains, and possibly molasses, salt and vitamins. Also, commercially sold products such as a product sold under the trade name RU-MIN-AID have been used as buffers or diet supplements. This product is believed to include calcium and magnesium and is believed to increase the ability of the ruminant animal to digest its food.
Animal research indicates that when the pH level of the digestant in the small intestines of beef cattle approaches 6.9, the animal is able to benefit more from the food substance, apparently by absorbing more of the nutrient value of its food. For example, when the pH level of the substance in the small intestines of beef cattle approaches 6.9, there is significantly less starch in the feces of the animal than when the pH level is lower. It is known that the bovine pancreatic alpha amylase do not function as well to digest the starch in the animal's food when the pH level of the food is substantially lower than 6.9. Research also indicates that some of the compounds mentioned above are effective in raising the pH level in the rumen and in the intestines of beef cattle.
In the manufacture of portland cement, the materials used to form the cement include limestone and clay, and the materials are ground together and raised to a high temperature in a kiln, in some instances up to about 2700.degree. F. The extreme heat in the kiln appears to cause the aluminum, calcium, magnesium, potassium and sodium to hydrate into hydroxide forms. During the heating process, a substantial amount of dust is given off, and in the past, the dust has been allowed to escape to the atmosphere. In more recent years, a substantial amount of the dust escaping from the cement manufacturing process has been extracted as a precipitate from the exhaust stacks of kilns, and treated as a waste product, usually by burying in pits or by dumping in rivers, etc. There appears to be no practical and profitable use for the precipitate dust from the manufacture of portland cement.